The present invention relates to a method for operating an internal combustion engine which includes at least one venting duct running from a crank chamber of a crankcase to an intake manifold as well as an air mass sensor for measuring a fresh air mass flow supplied to the internal combustion engine, wherein depending on the measured fresh air mass flow a cylinder charge of at least one cylinder of the internal combustion engine is determined based on the measured fresh air mass flow.
The present invention also relates to a control element for a controller of an internal combustion engine, in particular of an automobile.
The present invention furthermore relates to an internal combustion engine, in particular for an automobile, with a crankcase forming a crank chamber as well as at least one cylinder with which an intake manifold is associated, wherein a venting duct extends from the crank chamber to the intake manifold, with an air mass sensor for measuring a fresh air mass flow supplied to the internal combustion engine, and with first means for determining a cylinder charge of the cylinder as a function of the measured fresh air mass flow.
The following discussion of related art is provided to assist the reader in understanding the advantages of the invention, and is not to be construed as an admission that this related art is prior art to this invention.
The method, the control elements and the internal combustion engine of the aforedescribed type are known. When operating internal combustion engines, it is customary for attaining optimal combustion, for example in relation to torque and/or exhaust gas values, to match the fuel quantity and the fresh air mass supplied to the combustion chambers and to the cylinders, respectively, of the internal combustion engine. It is known to measure the fresh air mass flow supplied to the internal combustion engine and to determine therefrom a cylinder charge, i.e., the quantity of fresh air mass reaching the cylinders. An expected cylinder charge it is thus determined, to which the quantity of the injected fuel can be adapted.
It is also known to vent the crank chamber of the crankcase on a regular basis or continuously, for example to prevent the generation of combustible gases/vapors in the crank chamber. For this purpose, the crank chamber is connected to an intake manifold of the internal combustion engine by way of a venting duct. The crank chamber is vented or evacuated as a result of the suction effect of the fresh air mass flow flowing through the intake manifold on the venting duct. An actuatable valve may also be provided for venting commensurate with the demand.
Conventional methods and internal combustion engines have the disadvantage that the air mass sensor measures only the total fresh air mass supplied to the internal combustion engine, but does not measure changes in the mass flow occurring internally in the system. It was therefore thus far not possible at all or only by using additional sensors to take into consideration the additional gas mass, which reaches the intake manifold and also affects the cylinder charge, caused by the venting of the crank chamber.
It would therefore be desirable and advantageous to obviate prior art shortcomings and to provide an improved method, a control element and an internal combustion engine which takes into account system-internal mass flow changes affecting the cylinder charge in a simple and cost-effective manner.